Not just "could be prosecuted" — anyone can be "prosecuted" — but that almost everyone actually is guilty of a federal felony. Whether that has been proven is another issue. The problem, as Judge Kozinski points out, is that this enables selective prosecution. If an AUSA wants to indict you, they can probably find something you're in fact guilty of.

There are nowhere near the resources to prosecute every violation, nor even to litigate every prosecution currently being made (the vast supermajority of which are pled out). The justice system would be completely gridlocked if every criminal accusation actually had a full trial.

It's hard to imagine most the laws would remain on the books if everyone guilty (i.e. basically every person in the country) were actually prosecuted.